Patient information: Celiac disease in adults

CELIAC DISEASE OVERVIEW

Celiac disease is a condition in which the immune system responds abnormally to a protein called gluten, which can cause damage to the lining of the small intestine. Gluten is found in wheat, rye, barley, and a multitude of prepared foods. Celiac disease is also known as gluten sensitive enteropathy (enter-OH-pathy), celiac sprue, and nontropical sprue.

The small intestine is responsible for absorbing food and nutrients. Thus, damage to the lining of the small intestines can lead to difficulty absorbing important nutrients; this problem is referred to as malabsorption. Although celiac disease cannot be cured, avoiding gluten usually stops the damage to the intestinal lining and the malabsorption that results. Celiac disease can occur in people of any age and it affects both genders.

This topic discusses celiac disease in adults. Celiac disease in children is discussed separately. (See "Patient information: Celiac disease in children".) More detailed information about celiac disease is available by subscription. (See "Pathogenesis, epidemiology, and clinical manifestations of celiac disease in adults" and "Diagnosis of celiac disease" and "Management of celiac disease in adults".)

CELIAC DISEASE SYMPTOMS

The symptoms of celiac disease vary from one person to another. In its mildest form, there may be no symptoms whatsoever. However, even if you have no symptoms, you may not be absorbing nutrients adequately, which can be detected with blood tests. As an example, you can develop a low blood count as a result of decreased iron absorption.

Somoe people have bothersome symptoms of celiac disease, including diarrhea, weight loss, abdominal discomfort, excessive gas, and other signs and symptoms caused by vitamin and nutrient deficiencies.

Some conditions are more common in people with celiac disease, including:

• Osteopenia or osteoporosis (weakening of the bones)
• Iron deficiency anemia (low blood count due to lack of iron)
• Diabetes mellitus
• Thyroid problems (usually hypothyroidism, an underactive thyroid) (see "Patient information: Hypothyroidism")
• A skin disease called dermatitis herpetiformis (see 'Skin conditions' below)
• Nervous system disorders
• Liver disease

CELIAC DISEASE CAUSES

It is not clear what causes celiac disease. A combination of environmental and genetic factors are important since celiac disease occurs widely in Europe, North and South Americas, Australia, North Africa, the Middle East and in South Asia. Celiac disease occurs rarely in people from other parts of Asia or sub-Saharan Africa.

CELIAC DISEASE DIAGNOSIS

Celiac disease can be difficult to diagnose because the signs and symptoms are similar to other conditions. Fortunately, testing is available that can distinguish celiac disease from other disorders. (See "Diagnosis of celiac disease".)

Blood tests — A blood test can determine the blood level of antibodies (proteins) that become elevated in people with celiac disease. Over 90 percent of people with untreated celiac disease have elevated antibody levels, while these levels are rarely elevated in those without celiac disease.

Before having these tests, it is important to continue eating a normal diet, including foods that contain gluten. Avoiding or eliminating gluten could cause the antibody levels to be normal, delaying the diagnosis.

Small intestine biopsy — If your blood test is positive, the diagnosis must be confirmed by examining a small sample of the intestinal lining with a microscope. The sample (called a biopsy) is usually collected during an upper endoscopy, a test that involves swallowing a small flexible instrument with a camera. The camera allows a physician to examine the upper part of the gastrointestinal system and remove a small piece (biopsy) of the small intestine. The biopsy is not painful. (See "Patient information: Upper endoscopy".)

In people with celiac disease, the lining of the small intestine has a unique appearance when viewed with a microscope. Normally, the lining has distinct finger-like structures, which are called villi. Villi allow the small intestine to absorb nutrients. The villi become flattened in people with celiac disease. Once you stop eating gluten, the villi can resume a normal growth pattern. Approximately 70 percent of people begin to feel better within two weeks after stopping gluten.

One way to determine if the gluten free diet is working is to monitor the levels of antibodies in your blood. If your levels decline on a gluten free diet, this indicates that the diet has been effective.

"Latent" celiac disease — People with a positive IgA endomysial antibody test and/or a positive IgA-tTG test and a normal small bowel biopsy are considered to have latent celiac disease. People with latent disease are NOT usually advised to eat a gluten free diet. However, ongoing monitoring (with a blood test) is recommended and a repeat biopsy may be needed if you develop symptoms. Biopsies should be taken from several areas in the bowel since the abnormality can be patchy.

"Silent" celiac disease — If you have a positive blood test for celiac disease and an abnormal small bowel biopsy, but you have no other symptoms of celiac disease, you are said to have "silent" celiac disease. It is not clear if people with silent celiac disease should eat a gluten free diet. Blood tests for malabsorption are recommended, and a gluten free diet may be needed if you have evidence of malabsorption.

Testing for malabsorption — You should be tested for nutritional deficiencies if your blood test and bowel biopsy indicates celiac disease. Common tests include measurement of iron, folic acid, or vitamin B12, and vitamin D. You may have other tests if you have signs of mineral or fat deficiency, such as changes in taste or smell, poor appetite, changes in your nails, hair, or skin, or diarrhea.

Other tests — Other standard tests include a CBC (complete blood count), lipid levels (total cholesterol, HDL, LDL, and triglycerides), and thyroid levels. Once your celiac antibody levels return to normal, you should have a repeat test once per year.

Many clinicians recommend a test for bone loss 6 to 12 months after beginning a gluten free diet. One method involves using a bone density (DEXA) scan to measures your bone density. The test is not painful and is similar to having an x-ray. If you have significant bone loss, you may need a medicine to stop bone loss and encourage new bone growth. (See "Patient information: Bone density testing".)

CELIAC DISEASE COMPLICATIONS

Refractory celiac disease — A small percentage of people develop intestinal symptoms that do not improve despite use of a strict gluten free diet. In other cases, intestinal symptoms initially improve with dietary changes but then return.

People who have these problems are said to have refractory celiac disease. The cause of this problem is not known. Treatment involves medications that suppress the immune system's abnormal response (eg, steroids). Treatment is important because people with untreated celiac disease can develop anemia, bone loss, and other consequences of malabsorption.

Ulcerative jejunitis — People with refractory celiac disease who do not improve with steroids (glucocorticoids) may have a condition known as ulcerative jejunitis. This condition causes the small intestine to develop multiple ulcers that do not heal; other symptoms may include a lack of appetite, weight loss, abdominal pain, diarrhea, and fever. This condition can be difficult to treat. Treatment usually involves surgery to remove the ulcerated area.

Lymphoma — Cancer of the intestinal lymph system (lymphoma) is an uncommon complication of celiac disease. Avoiding gluten can usually prevent this complication.

Skin conditions — Celiac disease is associated with a number of skin disorders, of which dermatitis herpetiformis is the most common (table 1). Dermatitis herpetiformis is characterized by intensely itchy, raised, fluid filled areas on the skin, usually located on the elbows, knees, buttocks, lower back, face, neck, trunk and occasionally within the mouth (picture 1) and (picture 2).

The most bothersome symptoms are itching and burning. This feeling is quickly relieved when the blister ruptures. Scratching causes the area to rupture, dry up, and leave an area of darkened skin and scarring. The condition will improve after eliminating gluten from the diet, although it may take several weeks to see significant improvement. In the meantime, an oral medication called dapsone may be recommended. Dapsone relieves the itching but does not heal the lining of the small intestine; thus, the gluten free diet is the most effective therapy for those with Dermatitis herpetiformis.

CELIAC DISEASE TREATMENT

Gluten free diet — The cornerstone of treatment for celiac disease is complete elimination of gluten from the diet for life. Gluten is the group of proteins found in wheat, rye and barley that are toxic to those with celiac disease. Gluten is not only contained in these most commonly consumed grains in the Western world; it is also hidden as an ingredient in a large number of prepared foods, as well as medications and supplements.

Maintaining a gluten free diet is a challenging task that may require major lifestyle adjustments. Strict gluten avoidance is recommended since even small amounts can aggravate the disease. It is important to avoid both eating gluten and being exposed to it in the air. (See "Management of celiac disease in adults".)

Get help from a dietitian — Working with an experienced celiac dietitian can help you to learn how to eat a gluten free diet, what foods to avoid, and what foods to add for a nutritionally balanced diet.

Your celiac dietitian can also educate you on shopping, food preparation and lifestyle resources. Excellent resources are also available from celiac medical centers, organizations, and support groups. (See 'Where to get more information' below.)

Fortunately, life on a gluten free diet becomes increasingly easier each year due to the rising popularity of gluten free foods among those with celiac disease, gluten intolerance and wheat allergies. Excellent gluten free substitute foods are now widely available in supermarkets, health food stores, and on-line.

General tips

• Avoid foods containing wheat, rye, barley, malt, brewer's yeast, and oats (unless labeled gluten free).
• Naturally gluten free foods include rice, wild rice, corn, potato, and other foods listed in the table (table 2).
• Read labels on prepared foods and condiments carefully, paying particular attention to the "Contains" statement and the ingredient list. The word "wheat" will be included if the product is FDA regulated and it contains wheat. Table 3 has a list of prepared foods that sometimes contain gluten (table 3).
• You may not tolerate dairy products initially, while your intestines are healing. If you tolerated lactose before your diagnosis, you may be able to tolerate it again after the intestine heals. In the mean time, choose lactose-reduced or lactose-free products if your symptoms are worsened by dairy products. Choose gluten free, dairy-free alternatives, such as rice, soy, hemp, or nut (almond, hazelnut) beverages that are enriched with calcium and vitamin D. Gluten free lactase enzyme supplements are also available, which may help you to tolerate foods that contain lactose.
• Discuss your need for calcium and vitamin D supplements with your healthcare provider or dietitian.
• A small percentage of people with celiac disease cannot tolerate oats. If you choose to eat oats, consult with a healthcare provider or dietitian, who can help to monitor your symptoms. In addition, you should avoid oats unless the package specifically indicates that the product is gluten free and was processed in a gluten free facility. Do not eat more than 50 grams (about 1/2 cup dry rolled oats, 1/4 cup dry steel cut oats) of oats per day.

Is gluten avoidance really necessary? — People who have no symptoms of celiac disease often find it difficult to follow a strict gluten free diet. Indeed, some healthcare providers have questioned the need for a gluten free diet in this group. However, certain factors support a gluten free diet, even in those without symptoms:

• Strictly following a gluten free diet sometimes helps you to feel more energetic and have an improved sense of health and well being.
• Some people with celiac disease have vitamin or nutrient deficiencies that do not cause them to feel ill, such as anemia due to iron deficiency or bone loss due to vitamin D deficiency. However, these deficiencies can cause problems over the long term.
• Untreated celiac disease can increase the risk of developing certain types of gastrointestinal cancer. This risk can be reduced by eating a gluten free diet.

IMPLICATIONS FOR THE FAMILY

Eliminating gluten requires a major lifestyle change you as well as you family. However, with time and practice, it will be easier to know which foods, medications, supplements, and body care products contain gluten and what alternatives are available. Although eating out can be challenging initially, restaurants have become increasingly interested in serving people with celiac disease by offering a gluten free menu or ingredient substitutions.

Families also need to be aware of their increased risk of celiac disease. Thus, your first-degree relatives (parents, brothers, sisters, children) should consider being tested, especially if anyone has signs or symptoms of the condition. Testing is typically done with a blood antibody test, as described above (see 'Blood tests' above.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Celiac disease in children
Patient information: Hypothyroidism
Patient information: Upper endoscopy
Patient information: Bone density testing

Professional Level Information:
Diagnosis of celiac disease
Management of celiac disease in adults
Pathogenesis, epidemiology, and clinical manifestations of celiac disease in adults

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/celiacdisease.html)

• The Celiac Disease Foundation

       (www.celiac.org)

• Gluten Intolerance Group of North America

      (www.gluten.net)

• The Celiac Sprue Association

       (www.csaceliacs.org)

• American Celiac Disease Alliance

      (www.americanceliac.org)

• National Foundation for Celiac Awareness (NFCA)

      (www.celiacawareness.org)

Patient Support — There are a number of online forums where patients can find information and support from other people with similar conditions.

• About.com Celiac Disease Forum

      (http://celiacdisease.about.com/forum)

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